Educational multiplying device



Dec. 14, 1943. A. E, MAGUIRE 2,336,742

EDUCATIONAL MULTIPLYING DEVICE` Filed Decj 5 1941 Patented Dec. 14, 1943UNITED STATES PATENT OFFICE EDUCATIONAL MULTIPLYING DEVICE Amelia E.Maguire, Venice, Calif.

Application December 5, 1941, Serial No. 421,740

1 Claim.

My invention relates to a manually operable educational device and hasfor its principal object, the provision of a relatively simple,practical, and inexpensive device comprising a plurality of associateddiscs, certain of which are mounted for rotation on 'a single largedisc, and the rotatable discs bearing numbers which show the results ofthe multiplication of gures representing multiplicands that appear onthe face of the larger disc by figures representing multipliers andwhich latter appear on the rotatably mounted discs.

A further object of my invention is to provide a multiplying device thatincludes a disc provided in its edges with notches, with tabs projectingint-o said notches, said disc being mounted for rotation en the upper orfront disc that bears the figures representing the multiplicands andwhich notched disc may be rotated a short distance so as to bring thetabs thereon into position overlying the figures representing theresults o-n the small rotatably mounted discs, thus covering or blockingout said results in order to increase the efciency of the device whenused for teaching multiplication.

A further object of my invention is to provide `a device of thecharacter referred to that may function as an interesting andinstructive plaything, as well as a device for teaching multiplicationin schools and the like.

A further object of my invention is to provide an educationaldevice-which may by change of certain printed characters on the discs,be used for teaching division.

With the foregoing and other objects in view,

invention consists in certain novel features of ;`y

construction and arrangement of parts that will be hereinafter morefully described and claimed and illustrated in the accompanying drawingin which:

Fig. l is a top plan View of an educational multiplying deviceconstructed in accordance with my invention, with parts thereof brokenaway in order to more clearly illustrate certain parts that covered bythe upper or front disc.

Fig. 2 is a cross section taken on the line 2 2 of Fig. l.

Fig. 3 is a detail view showing the under or lower disc of the deviceshifted so that the tabs carried thereby cover the numerals designatingthe results and which numerals are printed on the i rotating discs.

Fig. 4 is a fragmentary plan view illustrating a modified construction.

Referring by numerals to the accompanying drawing which illustrate apreferred embodiment of my invention and which may be used formultiplying numbers from l to l2 inclusive, ID designates a disccomposed of thin, fairly stiff material, such as cardboard, Celluloid,or any of the commercial plastics now on the market, and formed in themarginal porton of this disc and extending inwardly from the edgethereof are rectangular notches II spaced equal distances apart. Seatedin the center of disc I 0 is a pivot I2, preferably a tubular rivet, andmounted to rotate freely thereupon is 'a disc I3 of thin material, thediameter of which is substantially equal to the diameter of the disc I0.

Formed in the marginal portion of the rotatably mounted disc I3 andspaced equal distances apart are notches I4 and projecting from one sideof each notch 'adjacent the periphery of the disc is a tab I5, andthewidth of these tabs is approximately equal to one-half the length of thenotches II in disc I0. The width of the space I6 between the end of eachtab I5 and the edge of notch I 4 opposite the edge from which said tabprojects is substantially equal to the Width of the notches I I. Thuswhen the disc I3 is shifted so that the spaces I6 coincide with theouter portions of the notches II, the tabs I5 close the outer portionsof the notches I I in disc I0.

Formed on the edge of disc I3 'are one or more small projections such asI'I which may be engaged by the linger for rotating said disc.

Seated in the disc I 0 at short distances inwardly from the inner endsof the notches I l are pivots I8, preferably tubular rivets, and mountedto rotate freely on the lower ends of said pivots immediately beneaththe disc I3 is a series of small discs I9 that bear on their upper facesthe numbers designating the multipliers and the results ofmultiplication processes.

Formed integral with the central portion of the shank of each of thesepivots I8 is a small rib or fiange 2) which serves to maintain the discsI9 in spaced relation with respect to the disc I0 for the accommodationof the disc I3. The pivot members I 8 extend through the notches I4 indisc I3 and said pivot members which vare engaged by the side edges ofthe notches I4 as disc I3 is shifted from one position to another, serveas stops to limit the rotary movement of said disc I3.

Appearing on the upper faces of the rotating discs I9 adjacent theirperipheries and spaced equal distances apart are numbers representingthe results of multiplication 'and appearing on the same faces of saiddiscs inwardly from the numbers indicating the results are numbersindicating the multipliers. Appearing between the numers representingthe multipliers and the numbers representing the results are the shortparallel lines that represent equal in mathematical computations.

Appearing on the upper face of the disc it between the pivot members I8and the inner ends of the notches Il are the numbers representingmultiplicands that are followed by the character representing times inmultiplication.

For teaching the standard multiplication table,

it will be understood that twelve of the small rotating discs i9 areused and that the numerals designating the multipliers and the resultsthat appear thereon run from 1 to 12 respectively. In other words, thedisc having the numerals designating the multipliers from 1 to 12inclusive and the numerals representing the results from 12 to 144inclusive is mounted on the pivot I3 that is adjacent the numeralsrepresenting the multiplicand that appears on the face of disc IUadjacent said pivot, .and this arrangement is carried out in the elevenother rotating discs I 9.

Thus the device equipped with twelve rotating discs IB and which latterbear on their upper faces the multipliers and results of multiplication,may be conveniently utilized for the multiplication of all numbers from1 to 12 inclusive. If desired, the size of the discs Iii and I 3 may beincreased in order to accommodate an increased number of the smallrotating discs I9, thereby increasing the multiplying capacity of thedevice.

In the use of the multiplying device, the discs i9 are rotated so as tosuccessively bring the multipliers and results that appear on the facesthereof into position directly below the notches l i and thus thestudent may readily observe vthe results attained by multiplication ofthe numbers designating the multiplie-ands which appear on the face ofthe disc Iii adjacent the inner ends of the notches l I,

During the instruction periods, the teacher o1' student may engage oneof the studs or projections Il and rotate the disc I3 so as to positionthe tabs I5 across the outer portions of the notches Ii, therebycovering all of the numerals on the discs I9 that represent the resultsof multiplication, and thus the student may be required to give theresults subsequent to learning the same, before the disc i3 was rotatedto cover the printed results (See Fig. 3).

By slight variation of the numbers printed on the discs It and vI9 andcorrespondingly changing the arithmetical signs following the numbersprinted on the disc It), my improved device mal be used for teaching toa limited degree problems in addition, subtraction, and division.

In the modified construction illustrated in Fig. 4, the disc Ii) isprovided inwardly from the pivots I3 that provide axes for the discs i9with a circular row of radially disposed slots 25 that provide sightopenings through which the numbers printed on the discs I9 are readilyvisible and which arrangement eliminates the notching of the marginalportion of said disc Ill. Where such construction is employed, thenumbers representing the multiplicancls are located between the pivotsIS and the slots 25.

Thus it will be seen that I have provided an educational multiplyingdevice that is relatively simple in construction, inexpensive ofmanufacture, and very effective in performing the functions for which itis intended, namely, the teaching of multiplication and particularly thestandard multiplication table.

t Will be understood that minor changes in the size, form andconstruction of the various parts of my improved educational multiplyingdevice, may be made and substituted for those herein shown anddescribed, without departing from the spirit of my invention, the scopeof which is set forth in the appended claim.

I claim as my invention:

In an educational multiplying device, a disc provided in its marginalportion with radial notches, a series of small discs mounted forrotation on the under side of said rst mentioned disc, portions of whichsmall discs are visible through the notches in said first mentioneddisc, said iirst mentioned disc bearing on its upper face adjacent theinner ends of the notches therein, numbers that represent multiplicands,the upper faces of the small discs bearing circular rows of figuresrepresenting multipliers and results that are complementary to themultiplicands appearing on the face of said rst mentioned disc, whichmultipliers and results are successively visible through the notches insaid first mentioned disc as said small discs are rotated, means forspacing the small discs apart fro-m the underface of said rst mentioneddisc a disc co-eXtensive with said first mentioned disc and mounted forrotation upon the center thereof, the outer portion of which rotativelymounted disc is positioned between said small discs and the outerportion of the `first mentioned disc, said rotative disc being providedin its outer portion with a series of spaced radial notches, the widthof the inner portions of whichradial notches and theaxes for the smalldiscs, limitl the rotative movement of rotative disc relative to thefirst mentioned disc and a tab projecting from the outer portion of theedge at one side -of each notch in said rotative disc for covering theresult appearing on the upper face of the adjacent small disc.

vAMELIA E. MAGUERE.

